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CN-122025623-A - Single crystal positive electrode material, and preparation method and application thereof

CN122025623ACN 122025623 ACN122025623 ACN 122025623ACN-122025623-A

Abstract

The application provides a single crystal positive electrode material, a preparation method and application thereof, wherein the thermal stability parameter S of the single crystal positive electrode material is more than 0.54, and S is calculated by a formula 1: In the formula 1, D is the average single crystal size of the single crystal positive electrode material, the unit is mu m, dv50 is dv50 of the single crystal positive electrode material, the unit is mu m, C is the discharge capacity of the single crystal positive electrode material under the 4.3V voltage 0.2C multiplying power, the unit is mAh/g, T and Q are the DSC curve peak temperature and the heat flow value of the single crystal positive electrode material under the 4.3V cut-off voltage, and the units are the temperature of DSC curve peak and the heat flow value of the single crystal positive electrode material. The parameters in the single crystal positive electrode material are mutually matched, so that S is more than 0.54, the thermal stability of the single crystal positive electrode material is effectively improved, and the safety of a battery is effectively improved.

Inventors

  • Ye Kongqiang
  • GUO XIAOHUA
  • LIN ZHEQI

Assignees

  • 宁波容百新能源科技股份有限公司

Dates

Publication Date
20260512
Application Date
20260116

Claims (10)

  1. 1.A single crystal positive electrode material, characterized in that the thermal stability parameter S of the single crystal positive electrode material is >0.54; Wherein S is calculated by formula 1: Formula 1; in the formula 1, D is the average single crystal size of the single crystal positive electrode material, the unit is mu m, dv50 is dv50 of the single crystal positive electrode material, the unit is mu m, C is the discharge capacity of the single crystal positive electrode material under the 4.3V voltage 0.2C multiplying power, the unit is mAh/g, T and Q are the DSC curve peak temperature and the heat flow value of the single crystal positive electrode material under the 4.3V cut-off voltage, and the units are the temperature of DSC curve peak and the heat flow value of the single crystal positive electrode material.
  2. 2. The single crystal positive electrode material according to claim 1, wherein S≥0.6, and/or, The D and dv50 satisfy 0.54< D/dv50<1.0.
  3. 3. The single crystal positive electrode material according to claim 1 or 2, wherein D is 2.7 to 6 μm, and/or, The dv50 is 4.6-7.5 mu m, and/or, The C is greater than or equal to 202mAh/g, and/or, The T is 225-240 ℃, and/or, Q is 6-30W/g.
  4. 4. The single crystal positive electrode material according to any one of claims 1 to 3, wherein the single crystal positive electrode material has a chemical formula of Li 1+a Ni x Co y M z X b O 2 , wherein 0.8< X <1,0< y <0.2, 0≤z <0.1,0< a <0.03, 0≤b <0.1, and x+y+z+b=1, M is at least one of Mn and/or Al, X is Zr, sr, la, Y, al, mg, nb, mo, ce, W, ti, B, P, and/or, The lithium nickel mixed discharge degree of the single crystal positive electrode material is less than or equal to 2.5 percent and/or, The single crystal positive electrode material has a layered structure of R-3m space group.
  5. 5. A method for producing the single crystal positive electrode material according to any one of claims 1 to 4, comprising the steps of: 1) Oxidizing the monocrystalline anode material precursor under the action of an oxidant to obtain a hydroxyl oxide precursor; 2) Pressurizing and activating a mixed system comprising the hydroxyl oxide precursor and an active ion source, and sequentially performing first sintering treatment and second sintering treatment on an activated product to obtain a monocrystal anode material precursor, wherein the temperature of the first sintering treatment is 400-600 ℃, and the temperature of the second sintering treatment is 850-1000 ℃; 3) And sequentially performing a first cooling process, a second cooling process and a third cooling process on the monocrystal positive electrode material precursor, wherein the temperature of a platform in the first cooling process is 850-880 ℃, the heat preservation time is 4-6 hours, the temperature of a platform in the second cooling process is 800-850 ℃, the heat preservation time is 3-5 hours, and the temperature of a platform in the third cooling process is 700-800 ℃ and the heat preservation time is 2-4 hours.
  6. 6. The process of claim 5, wherein the mixing system further comprises an X source, and/or, The pressurized activation treatment comprises the steps of carrying out a hydrothermal reaction on a mixed system comprising a hydroxyl oxide precursor and a lithium source under the pressure of 1-10Mpa to obtain a lithiation product, wherein the temperature of the hydrothermal reaction is 100-200 ℃ and the time is 10-20 h, and/or, The temperature rising speed of the first sintering treatment is 3-5 ℃ per minute, the heat preservation time is 4-8 hours, the temperature rising speed of the second sintering treatment is 1-3 ℃ per minute, and the heat preservation time is 6-10 hours.
  7. 7. The method according to claim 6, wherein the oxidizing agent comprises at least one of ozone, hydrogen peroxide and potassium permanganate, and/or, The concentration of the oxidant is 100-150 mg/L, and/or, The concentration of lithium ions in the mixed system is 3-10 mol/L, and/or, The content of the X element in the X source in the mixed system is 500-5000 ppm.
  8. 8. The method according to any one of claims 5 to 7, wherein the cooling rate in the first cooling process is 0.5 to 1 ℃ per minute, the cooling rate in the second cooling process is 1 to 2 ℃ per minute, and the cooling rate in the third cooling process is 2 to 4 ℃ per minute.
  9. 9. A positive electrode sheet comprising a positive electrode current collector and a positive electrode active layer provided on at least a part of the surface of the positive electrode current collector, wherein the positive electrode active layer comprises the single crystal positive electrode material according to any one of claims 1 to 4 or the single crystal positive electrode material obtained by the production method according to any one of claims 5 to 8.
  10. 10. A battery comprising the positive electrode sheet according to claim 9.

Description

Single crystal positive electrode material, and preparation method and application thereof Technical Field The application relates to the technical field of batteries, in particular to a monocrystalline anode material and a preparation method and application thereof. Background The secondary battery is used as a new generation green high-energy chemical power supply, has the advantages of high energy density, repeated charge and discharge and the like, and is widely applied to the fields of consumer electronics, electric automobiles, large-scale energy storage systems and the like. The positive electrode material is used as a core component of the positive electrode plate of the battery, and the performance of the positive electrode material directly influences the overall electrochemical performance of the battery. Conventional polycrystalline materials, such as NCM or NCA, are a research hotspot due to their higher specific capacity and energy density. However, the material is formed into a polycrystalline structure by a large number of primary particles, and is easy to generate structural degradation in the cycle process of the battery, so that side reactions are aggravated, and the cycle life and stability of the battery are restricted. In contrast, the monocrystal positive electrode material has no obvious crystal boundary, so that the lattice stress caused in the ion deintercalation process can be well restrained, the generation and development of microcracks are reduced at the source, and the risk of structural degradation is reduced. Nevertheless, the thermal stability of the single crystal material is still difficult to be expected, and the safety of the battery is restricted. Therefore, how to improve the safety of the battery by improving the thermal stability of the single crystal cathode material remains a key problem to be solved currently. Disclosure of Invention The application provides the monocrystalline cathode material, and the thermal stability of the monocrystalline cathode material is effectively improved by adjusting and controlling the mutual matching of different physical and chemical parameters of the monocrystalline cathode material, so that the safety of a battery is effectively improved. The application also provides a preparation method for preparing the single crystal positive electrode material, which has simple process and is suitable for mass production. The application also provides a positive plate which comprises the single crystal positive electrode material, so that the positive plate has the advantage of high thermal stability. The application also provides a battery which comprises the positive plate, so that the battery has the advantage of good safety performance. The application provides a single crystal positive electrode material, wherein the thermal stability parameter S of the single crystal positive electrode material is more than 0.54; Wherein S is calculated by formula 1: Formula 1; in the formula 1, D is the average single crystal size of the single crystal positive electrode material, the unit is mu m, dv50 is dv50 of the single crystal positive electrode material, the unit is mu m, C is the discharge capacity of the single crystal positive electrode material under the 4.3V voltage 0.2C multiplying power, the unit is mAh/g, T and Q are the DSC curve peak temperature and the heat flow value of the single crystal positive electrode material under the 4.3V cut-off voltage, and the units are the temperature of DSC curve peak and the heat flow value of the single crystal positive electrode material. The single crystal positive electrode material as described above, wherein S is not less than 0.6, and/or wherein D and dv50 satisfy 0.54< D/dv50<1.0. The single crystal positive electrode material is characterized in that D is 2.7-6 mu m, dv50 is 4.6-7.5 mu m, C is greater than or equal to 202mAh/g, T is 225-240 ℃ and Q is 6-30W/g. The single crystal positive electrode material has a chemical formula of Li 1+aNixCoyMzXbO2, wherein 0.8< X <1,0< y <0.2, 0≤z <0.1,0< a <0.03, 0≤b <0.1, and x+y+z+b=1, M is Mn and/or Al, X is at least one of Zr, sr, la, Y and Al, mg, nb, mo, ce, W, ti, B, P, and/or the lithium nickel miscibility degree of the single crystal positive electrode material is less than or equal to 2.5%, and/or the single crystal positive electrode material has a layered structure of R-3m space group. The application further provides a preparation method of the single crystal positive electrode material, which comprises the steps of 1) oxidizing a single crystal positive electrode material precursor under the action of an oxidant to obtain a hydroxyl oxide precursor, 2) carrying out pressurized activation treatment on a mixed system comprising the hydroxyl oxide precursor and an active ion source, and then sequentially carrying out first sintering treatment and second sintering treatment on an activated product to obtain the single crystal positive electrode